A polycarbonate-polyorganosiloxane copolymer (hereinafter sometimes abbreviated as “PC-POS copolymer”) has been attracting attention because of its excellent properties, such as high impact resistance, chemical resistance, and flame retardancy. Accordingly, the polycarbonate-polyorganosiloxane copolymer has been expected to be widely utilized in various fields, such as the field of electrical and electronic equipment and the field of automobiles. In particular, the utilization of the polycarbonate-polyorganosiloxane copolymer in casings for a cellular phone, a mobile personal computer, a digital camera, a video camera, an electric tool, and the like, and in other commodities has been expanding.
In normal cases, a homopolycarbonate using 2,2-bis(4-hydroxyphenyl)propane [common name: bisphenol A] as a dihydric phenol serving as a raw material has been generally used as a typical polycarbonate. A polycarbonate-polyorganosiloxane copolymer using a polyorganosiloxane as a copolymerizable monomer has been known for improving the physical properties of the homopolycarbonate, such as flame retardancy and impact resistance (Patent Document 1).
Examples of an approach to further improving the impact resistance of a polycarbonate resin containing the polycarbonate-polyorganosiloxane copolymer may include an approach involving using a polyorganosiloxane having a long chain length, and an approach involving increasing the amount of the polyorganosiloxane in the polycarbonate-polyorganosiloxane copolymer as described in Patent Documents 2 and 3.